List Serialization and Deserialization by binary formatter - list

Question

I have a class. I wanna serialize and the serialize a list that contains object of that class. I want to use binary formatter.
This is my class:
[Serializable]
public class Section :ISerializable
{
private double ClearCover;
private string SectionName;
private double Diameter;
public double Height;
private double Width;
private double InternalDiameter;
private double ExternalDiameter;
private double InternalHeight;
private double ExternalHeight;
private double InternalWidth;
private double ExternalWidth;
private double WebWidth;
private double FlangeWidth;
private double FlangeThickness;
public double clearCover
{
get { return ClearCover; }
set { ClearCover = value; }
}
public string sectionName
{
get{return SectionName;}
set{SectionName=value;}
}
public double diameter
{
get { return Diameter; }
set { Diameter = value; }
}
public double height
{
set { Height = value; }
get { return Height; }
}
public double width
{
set { Width = value; }
get { return Width; }
}
public double internalDiameter
{
set { InternalDiameter = value; }
get { return InternalDiameter; }
}
public double externalDiameter
{
set { ExternalDiameter = value; }
get { return ExternalDiameter; }
}
public double internalHeight
{
set { InternalHeight = value; }
get { return InternalHeight; }
}
public double externalHeight
{
set { ExternalHeight = value; }
get { return ExternalHeight; }
}
public double internalWidth
{
set { InternalWidth = value; }
get { return InternalWidth; }
}
public double externalWidth
{
set { ExternalWidth = value; }
get { return ExternalWidth; }
}
public double flangeWidth
{
set { FlangeWidth = value; }
get { return FlangeWidth; }
}
public double flangeThickness
{
set { FlangeThickness = value; }
get { return FlangeThickness; }
}
public double webWidth
{
set { WebWidth = value; }
get { return WebWidth; }
}
public Section() { }
protected Section(SerializationInfo info, StreamingContext context)
{
sectionName = info.GetString("Section Name");
clearCover = info.GetDouble("Clear Cover");
diameter = info.GetDouble("Diameter");
//internalDiameter = info.GetDouble("Internal Diameter");
//externalDiameter = info.GetDouble("External Diameter");
height = info.GetDouble("Height");
width = info.GetDouble("Width");
internalHeight = info.GetDouble("Internal Height");
externalHeight = info.GetDouble("External Height");
internalWidth = info.GetDouble("Internal Width");
externalWidth = info.GetDouble("External Width");
flangeWidth = info.GetDouble("Flange Width");
flangeThickness = info.GetDouble("Flange Thickness");
webWidth = info.GetDouble("Web Width");
}
public virtual void GetObjectData(SerializationInfo info, StreamingContext context)
{
info.AddValue("Section Name", sectionName);
info.AddValue("Clear Cover", clearCover);
info.AddValue("Diameter",diameter);
//info.AddValue("Internal Diameter", internalDiameter);
//info.AddValue("External Diameter", externalDiameter);
info.AddValue("Height",height);
info.AddValue("Width",width);
info.AddValue("Internal Height",internalHeight);
info.AddValue("External Height",externalHeight);
info.AddValue("Internal Width",internalWidth);
info.AddValue("External Width",externalWidth);
info.AddValue("Flange Width",flangeWidth);
info.AddValue("Flange Thickness", flangeThickness);
info.AddValue("Web Width", webWidth);
}
}
I don't have any problem in serialization. But for deserialize, it can just deserialize first object not all of them. What should I do, please help me!

Answer 1

From a separate email from the OP, the following methods were obtained (I've tidied them a little, not much):
static void Serialize(object obj, string filename)
{
using (FileStream streamOut = new FileStream(filename, FileMode.Append))
{
BinaryFormatter formatter = new BinaryFormatter();
formatter.Serialize(streamOut, obj);
}
}
public static List<Section> DeserializeList(string filename)
{
using (FileStream streamIn = File.OpenRead(filename))
{
BinaryFormatter formatter = new BinaryFormatter();
return (List<Section>) formatter.Deserialize(streamIn);
}
}
The key observation here is that it is assuming that BinaryFormatter is an appendable format, and that serializing two objects sequentially is the same as serializing 2 items at the same time (a list), for example:
if(File.Exists("foo.bin")) File.Delete("foo.bin"); // start afresh
Serialize(new Section { Diameter = 1.2, ClearCover = 3.4 }, "foo.bin");
Serialize(new Section { Diameter = 5.6, ClearCover = 7.8 }, "foo.bin");
var clone = DeserializeList("foo.bin");
However, that simply is not the case. To deserialize the items in this way, we would have to do something like:
public static List<Section> DeserializeList(string filename)
{
using (FileStream streamIn = File.OpenRead(filename))
{
List<Section> list = new List<Section>();
BinaryFormatter formatter = new BinaryFormatter();
while(streamIn.Position != streamIn.Length)
{
list.Add((Section) formatter.Deserialize(streamIn));
}
return list;
}
}
which it a little vexing - not least because it can't be applied to all streams (.Length and even .Position are not universally available).
The above should work, but I would strongly advise using an appendable format, such as protobuf. In fact, protobuf-net makes this scenario effortless, both in terms of the model:
[ProtoContract]
public class Section
{
[ProtoMember(1)] public double ClearCover { get; set; }
[ProtoMember(2)] public string SectionName { get; set; }
[ProtoMember(3)] public double Diameter { get; set; }
[ProtoMember(4)] public double Height { get; set; }
[ProtoMember(5)] public double Width { get; set; }
[ProtoMember(6)] public double InternalDiameter { get; set; }
[ProtoMember(7)] public double ExternalDiameter { get; set; }
[ProtoMember(8)] public double InternalHeight { get; set; }
[ProtoMember(9)] public double ExternalHeight { get; set; }
[ProtoMember(10)] public double InternalWidth { get; set; }
[ProtoMember(11)] public double ExternalWidth { get; set; }
[ProtoMember(12)] public double FlangeWidth { get; set; }
[ProtoMember(13)] public double FlangeThickness { get; set; }
[ProtoMember(14)] public double WebWidth { get; set; }
}
and the serialization / deserialization:
static void Main()
{
if (File.Exists("foo.bin")) File.Delete("foo.bin"); // start afresh
Serialize(new Section { Diameter = 1.2, ClearCover = 3.4 }, "foo.bin");
Serialize(new Section { Diameter = 5.6, ClearCover = 7.8 }, "foo.bin");
var clone = DeserializeList("foo.bin");
}
static void Serialize(object obj, string filename)
{
using (FileStream streamOut = new FileStream(filename, FileMode.Append))
{
Serializer.NonGeneric.SerializeWithLengthPrefix(
streamOut, obj, PrefixStyle.Base128, Serializer.ListItemTag);
}
}
public static List<Section> DeserializeList(string filename)
{
using (FileStream streamIn = File.OpenRead(filename))
{
return Serializer.DeserializeItems<Section>(
streamIn, PrefixStyle.Base128, Serializer.ListItemTag).ToList();
}
}
Finally, the BinaryFormatter data for those 2 rows was 750 bytes; with protobuf-net: 40 bytes.